The present invention relates to a method of manufacturing ceramic multi-layer boards to be used as a small component of personal computers and cellular phones.
A conventional ceramic multi-layer board is disclosed in, e.g., Japanese Patent Application Non-Examined Publication No. H11-220260. FIG. 11 illustrates the ceramic multi-layer board disclosed in the foregoing publication. This board is manufactured by a conventional method of laminating green-sheets.
As shown in FIG. 11(a), conductive patterns 13, 14 are printed on each green sheet 12. Then as shown in FIG. 11(b), respective green sheets 12 are laminated, and undergo a bonding process by heat and pressure to be integrated. The integrated product is then fired. In this conventional method; however, the shrinkage due to debindering and firing occurs in the product shown in FIG. 11(b). This shrinkage occurs in both a thickness direction and an in-plane direction of the multi-layer board. The shrinkage along the in-plane direction, in particular, influences dimensions of the conductive patterns. Dispersion due to this firing shrinkage is approx. 0.2%. To be more specific, when a board is sized 50 mm square, a dimensional accuracy (dispersion) of the conductive patterns falls within a range of xc2x1100 xcexcm.
Under the present circumstances, boards are mounted with components at a higher density, and a bonding pad is required to have a narrower pitch (not more than 150 xcexcm). Thus the conventional method of laminating green-sheets invites short-circuits in the inner conductive patterns, and it is hard to manufacture electronic components of desirable performance by this conventional method.
A method of manufacturing ceramic multi-layer boards is disclosed. The method including the steps of:
forming a adhesive layer on at least one surface of a ceramic board;
forming conductive patterns on the adhesive layer;
providing green sheet (GS) on top of the conductive patterns by applying heat and pressure;
forming conductive patterns on the GS;
laminating conductive patterns and GS one after another more than once; and
firing the laminated ceramic board thus formed and undergone a debindering process.